Not applicable.
It is estimated that one out of eight women will face breast cancer at some point during her lifetime, and for women age 40-55, breast cancer is the leading cause of death. While methods for detecting and treating breast cancer initially were crude and unsophisticated, advanced instrumentation and procedures now are available which provide more positive outcomes for patients.
In the 1800s the only treatment for breast cancer was removal of the entire breast. Given that the sole method of detection and diagnosis was palpation, treatment was only directed when the breast tumor was well advanced. Modified radical mastectomies are still performed today for patients with invasive cancer, such a procedure involving the removal of the entire breast and some or all of the axillary lymph nodes. Radical or modified radical mastectomies involve serious trauma for the patient during surgery with the severest cosmetic results after surgery.
Another surgical option upon the discovery of malignant tumor is what is referred to as breast conserving surgery, which also is referred to as lumpectomy, tumorectomy, segmental mastectomy and local excision. Meant to address the cosmetic concerns associated with removal of the breast, only the primary tumor and a margin of surrounding normal breast tissue is removed. Determining the proper amount of tissue to be removed involves balancing the need to take sufficient tissue to prevent recurrence with the desire to take as little tissue as possible to preserve the best cosmetic appearance. A more limited nodal dissection now is performed with the primary purpose being staging rather than therapy. While an improvement over radical mastectomy, breast-conserving surgery still involves the removal of large sections of breast tissue. Risks associated with such surgery include wound infection, seroma formation, mild shoulder dysfunction, loss of sensation in the distribution of the intercostobrachial nerve, and edema of the breast and arm. For more information on invasive tumor therapy, see:
(1) Harris, Jay R., et al. xe2x80x9cCancer of the Breast.xe2x80x9d Cancer: Principles and Practices of Oncology, Fourth Edition. Eds. DeVita, et al. Philadelphia: J.B. Lippincott Co., 1993. 1264-1285.
(2) Jobe, William E. xe2x80x9cHistorical Perspectives.xe2x80x9d Percutaneous Breast Biopsy. Eds. Parker, et al. New York: Raven Press, 1993. 1-5.
Mastectomies and breast-conserving surgeries generally are procedures utilized for invasive tumor. Advances in tumor detection, however, have radically changed the course of diagnosis and treatment for a tumor. With the advent of imaging devices, such as the mammogram, suspect tumor may be located when it is of relatively small size. Today, tumor detection generally involves both a mammogram and a physical examination, which takes into account a number of risk factors including family history and prior occurrences. Technical improvements in mammogram imaging include better visualization of the breast parenchyma with less exposure to radiation, improvements in film quality and processing, improved techniques for imaging, better guidelines for the diagnosis of cancer and greater availability of well-trained mammographers. With these advancements in imaging technology, a suspect tumor may be detected which is 5 mm or smaller. More recently substantial progress has been witnessed in the technical disciplines of magnetic resonance imaging (MRI) and ultrasound imagining. With these advances, the location of a lesion is observable as diagnosticlanalytic or therapeutic procedures are carried out.
In the past, because a tumor normally was not discovered until it had reached an advanced stage, the issue of whether a tumor was malignant or benign did not need to be addressed. With the ability to locate smaller areas of suspect tumor, this issue becomes of critical importance, particularly in light of the fact that only 20% of small, non-invasive tumors are malignant. Tumors identified as being benign may be left in situ with no excision required, whereas action must be taken to excise suspect tissue confirmed to be malignant. In view of the value of classifying a tumor as malignant or benign, breast biopsy has become a much-utilized technique with over 1 million biopsies being performed annually in the United States. A biopsy procedure involves the two step process of first locating the tumor then removing part or all of the suspect tissue for examination to establish precise diagnosis.
One biopsy option available upon detection of a suspect tumor is an open surgical biopsy or excisional biopsy. Prior to surgery, a radiologist, using mammography, inserts a wire into the breast to locate the tumor site. Later during surgery, the surgeon makes an incision in the breast and removes a large section of breast tissue, including the suspect tissue and a margin of healthy tissue surrounding the tumor. As with other similar procedures, such as those described above, open surgery may result in high levels of blood loss, scarring at the location of the incision and permanent disfigurement, due to the removal of relatively large amounts of tissue. Because of the critical prognostic significance of tumor size, the greatest advantage of the excisional biopsy is that the entire area of the suspect tumor is removed. After being removed and measured, the specimen is split by a pathologist in a plane that should bisect a tumor if present, then the margin between tumor and healthy tissue is examined. Microscopic location of carcinoma near the margin provides information for future prognosis. Thus the pathology laboratory is oriented to the morphological aspect of analysis, i.e. the forms and structures of involved tissue.
For information on pathology of breast biopsy tissue, see:
(3) Rosen, Paul Peter. Rosen""s Breast Pathology.
Philadelphia: Lippincott-Raven Publishers, 1997. 837-858.
Other less invasive options are available which avoid the disadvantages associated with open surgery. One such non-invasive option is that of needle biopsy, which may be either fine needle aspiration or large core. Fine needle aspiration (FNA) is an office procedure in which a fine needle, for example of 21 to 23 gauge, having one of a number of tip configurations, such as the Chiba, Franzeen or Turner, is inserted into the breast and guided to the tumor site by mammography or stereotactic imaging. A vacuum is created and the needle moved up and down along the tumor to assure that it collects targeted cellular material. Generally, three or more passes will be made to assure the collection of a sufficient sample. Then, the needle and the tissue sample are withdrawn from the breast.
The resulting specimen is subject to a cytologic assay, as opposed to the above-noted morphological approach. In this regard, cell structure and related aspects are studied. The resultant analysis has been used to improve or customize the selection of chemotherapeutic agents with respect to a particular patient.
While a fine needle aspiration biopsy has the advantages of being a relatively simple and inexpensive office procedure, there are some drawbacks associated with its use. With fine needle aspiration, there is a risk of false-negative results, which most often occurs in cases involving extremely fibrotic tumor. In addition, after the procedure has been performed there may be insufficient specimen material for diagnosis. Finally, with fine needle aspiration alone the entire area of suspect tissue is not removed. Rather, fragmented portions of tissue are withdrawn which do not allow for the same type of pathological investigation as the tissue removed during an open surgery biopsy.
This limitation also is observed with respect to large core needle biopsies. For a large core needle biopsy, a 14 to 18 gauge needle is inserted in the breast having an inner trocar with a sample notch at the distal end and an outer cutting cannula. Similar to a fine needle aspiration, tissue is drawn through the needle by vacuum suction. These needles have been combined with biopsy guns to provide automated insertion that makes the procedure shorter and partially eliminates location mistakes caused by human error. Once inserted, multiple contiguous tissue samples may be taken at a time.
Samples taken during large core needle biopsies may be anywhere from friable and fragmented to large pieces 20 to 30 mm long. These samples may provide some histological data, unlike fine needle aspiration samples, however, they still do not provide the pathological information available with an open surgical biopsy specimen. Further, as with any mechanical cutting device, excessive bleeding may result during and following the procedure. Needle biopsy procedures are discussed in:
(4) Parker, Steve H. xe2x80x9cNeedle Selectionxe2x80x9d and xe2x80x9cStereotactic Large-Core Breast Biopsy.xe2x80x9d Percutaneous Breast Biopsy. Eds. Parker, et al. New York: Raven Press, 1993. 7-14 and 61-79.
A device which is somewhere between a needle biopsy and open surgery is referred to as the Advanced Breast Biopsy Instrumentation (ABBI). With the ABBI procedure, the practitioner, guided by stereotactic imaging, removes a core tissue sample of 5 mm to 20 mm in diameter. While the ABBI has the advantage of providing a large tissue sample, similar to that obtained from an open surgical biopsy, the cylindrical tissue sample is taken from the subcutaneous tissue to an area beyond the suspect tumor. For tumors embedded more deeply within the breast, the amount of tissue removed is considerable. In addition, while less expensive than open surgical biopsy, the ABBI has proven expensive compared to other biopsy techniques, and it has been noted that the patient selection for the ABBI is limited by the size and location of the tumor, as well as by the presence of very dense parenchyma around the tumor. For discussion on the ABBI, see:
(5) Parker, Steve H. xe2x80x9cThe Advanced Breast Biopsy Instrumentation: Another Trojan Hourse?xe2x80x9d Am. J.
Radiology 1998; 171: 51-53.
(6) D""Angelo, Philip C., et al. xe2x80x9cStereotactic Excisional Breast Biopsies Utilizing the Advanced Breast Biopsy Instrumentation System.xe2x80x9d Am J Surg. 1997; 174: 297-302.
(7) Ferzli, George S., et al. xe2x80x9cAdvanced Breast Biopsy Instrumentation: A Critique.xe2x80x9d J Am Coll Surg 1997;
185: 145-151.
Another biopsy device has been referred to as the Mammotome and the Minimally Invasive Breast Biopsy (MIBB). These devices carry out a vacuum-assisted core biopsy wherein fragments of suspect tissue are removed with a 11 to 14 gauge needle. While being less invasive, the Mammotome and MIBB yields only a fragmentary specimen for pathological study. These devices therefore are consistent with other breast biopsy devices in that the degree of invasiveness of the procedure necessarily is counterbalanced against the need for obtaining a tissue sample whose size and margins are commensurate with pathology requirements for diagnosis and treatment.
In a co-pending application for United States patent entitled xe2x80x9cMinimally Invasive Intact Recovery of Tissuexe2x80x9d, Ser. No. 09/472,673, filed Dec. 27, 1999 by Eggers, et al, an instrument for removing a targeted tissue volume in a minimally invasive manner is described. That instrument includes a tubular delivery cannula of minimum outer diameter, the tip of which is positioned in confronting adjacency with a tissue volume to be removed. Following such positioning, the electrosurgically excited leading edge of a capture component is extended forwardly from the instrument tip to enlarge while electrosurgically cutting and surrounding or encapsulating a tissue volume, severing it from adjacent healthy tissue. Following such capture, the instrument and encaptured tissue volume are removed through an incision of electively limited extent.
The present invention is addressed to apparatus, system and method for retrieving a tissue volume in intact form utilizing surgical instrumentation which is minimally invasive. This instrumentation includes a tubular delivery cannula of minimum outer diameter, the tip or distal end of which is positioned in confronting adjacency with the target tumor or tissue volume to be removed. Such positioning is facilitated through the utilization of a forwardly disposed precursor electrosurgical electrode assembly. Located within the interior channel of this delivery cannula is a capture component configured with a plurality of relatively elongate leafs mutually interconnected at their base to define a polygonal cross-sectional configuration. Each of the leafs terminates forwardly with a transversely bent, eyelet containing tip. Slidably extending through each eyelet is an electrically conductive pursing cable of a pursing cable assembly which is then attached to another leaf tip and extends rearwardly through a small, flexible guide tube attached to the leaf for connection with the cable terminator component of a drive assembly. The drive assembly is driven forwardly by a motor, translation assembly and abuttably engaged transfer assembly to actuate the capture component. This actuation is carried out by electrosurgically exciting the pursing cable assembly to establish a cutting leading edge. Then, the leafs, carrying the excited cable assembly, are driven at an attack angle mutually outwardly through a guidance assembly to an extent that the cutting leading edge reaches an effective maximum diameter extending about the tissue volume. At this juncture, the cable terminator encounters a stop member and the leaf tips are drawn mutually inwardly to define a curvilinear profile to close the leading edge about the tissue volume as their forward movement continues. These pursing cables, now under stress and constrained within the guide tubes at the outer surfaces of the leafs, contribute to the structural stability of the resultant tissue specimen containment structure. Adjustment of the number of leafs associated with a given cable establishes the rates of containment closure as well as the degree or extent of curvature of the noted curvilinear profile. Following capture, the instrument is removed from adjacent tissue with the retained tissue specimen.
By employing this noted cable terminator and stop member construction, the diameter of the delivery cannula can be maintained at a constant minimum value, while the instrument enjoys the capability of providing an important range of capture component leading edge maximum effective diameters. The relatively straightforward structuring of the delivery cannula, capture component and drive assembly permits their fabrication as a discrete disposable component, removably insertable within a hand maneuvered housing.
Practitioner control over the instrument principally is provided from either three button-type switches mounted upon its housing assembly or from a three pedal footswitch. A remotely located electrosurgical generator and control assembly is coupled by cable with the housing assembly and footswitch. In carrying out the retrieval procedure, following preliminary self checks for proper electrode and instrument connections and transfer assembly positioning, either a position switch on the housing or the footswitch is actuated by the practitioner. This energizes a forwardly disposed precursor electrode from the electrosurgical generator, initially at a boost voltage level for a short boost interval, then at a lower, normal cutting voltage level as the forward region of the delivery cannula is positioned in confronting adjacency with the involved tissue volume. The switch utilized then is released to terminate this positioning mode of the procedure.
The delivery cannula being thus positioned, the practitioner momentarily depresses an arm capture switch button on the housing assembly to cause the control assembly to enter an arm capture mode which disables the housing mounted position switch. Next, the practitioner depresses either the capture switch or capture footswitch which now performs a capture function. Upon depressing and continuing to depress a capture switch mounted upon the housing assembly or the capture footswitch, the control assembly enters a capture mode. At the commencement of this capture mode, motor performance initially is tested, whereupon the motor is de-energized as electrosurgical current at the boost voltage level is applied to the capture component cables for a short boost interval. Following this boost interval, current at a lower, normal cutting voltage level is asserted from the electrosurgical generator in conjunction with activation of the motor drive and the leafs commence to be deployed from the guidance assembly. During the ensuing actuation of the capture component under motor drive, the load characteristics of the motor are monitored for both motor performance and for detecting the completion of capture. In the latter regard, a forward stall condition is detected to determine capture completion commencing a capture complete mode. In this capture complete mode, motor rotational direction is reversed to cause a return of the transfer assembly to its original or home position, thus releasing the drive assembly of the disposable component from engagement. The delivery cannula with captured tissue specimen is removed from the incision and the disposable component of the instrument is removed from the housing assembly. When so removed, the practitioner may manually retract the drive component to a position causing the capture component leafs and associated pursing cable assembly to assume an open cup formation permitting facile access to the recovered specimen.
If, during the capture mode, the practitioner wishes to halt the procedure, the capture switch or capture footswitch is released to cause the control assembly to enter a pause mode. In this pause mode the motor is de-energized and electrosurgical cutting current to the capture component cable assembly is terminated. Return to capture mode performance is carried out by the practitioner by again depressing the handle mounted capture switch or capture footswitch.
The remotely disposed electrosurgical generator is configured with an input treatment network which responds to a conventional power input to derive an interim direct current (d. c.) voltage output of relatively higher value, for example, 380 volts. This input treatment preferably includes both EMI filtering as well as power factor correction. In general, a boost converter network is employed in conjunction with this power factor correction. The interim d. c. voltage then is applied to a 100 kilohertz inverter which provides a rectangular waveform output, the peak-to-peak voltage amplitude of which is developed by an inverter control network which performs in a resonant transition phase shift mode to achieve soft switching and quite accurate control of the noted voltage amplitude. This amplitude controlled output then is directed through an isolation transformer to rectification and filtering to evolve a d.c. link voltage, the amplitude of which is used as a control for the voltage amplitude of the ultimately derived electrosurgical boost and normal cutting voltage levels. In this regard, the d. c. link voltage input is directed to the input of a resonant tank circuit for deriving a sinusoidal output at a stable electrosurgical frequency which is directed to the primary side of a high voltage transformer. From the secondary side of that high voltage transformer, an output stage directs electrosurgical energy to the precursor electrodes and, alternately, to the capture component cable assembly. To provide control over the assertion of electrosurgical energy, the system employs a relay disconnect function within the d. c. link voltage circuit path.
The housing assembly also incorporates a manually graspable stabilizer grip which is removably connectable at either side of the instrument to accommodate both right handed and left handed practitioners. Further, the grip is adjustable longitudinally to accommodate for the size of the hand of the practitioner to facilitate reaching the three button switches mounted upon the housing assembly.
Other objects of the invention, will in part, be obvious and will, in part, appear hereinafter. The invention, accordingly, comprises the method, system and apparatus possessing the construction, combination of elements, arrangement of parts and steps which are exemplified in the following detailed description. For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in connection with the accompanying drawings.